Monitoring of the electromagnetic (EM) field environment surrounding antennas is desirable because regulations exist which stipulate maximum radiation emissions to which humans should be exposed. Measurement devices that can monitor electromagnetic field strength are commercially available and generally known in the art. Such monitoring devices may provide accurate (on the spot) measurements of electromagnetic fields.
The installation of mobile communication antenna systems is prevalent in many urban areas due to the increase in use of mobile telephones and the like. The increased deployment of radio base stations has raised worldwide public concern regarding exposure of RF (radio frequency) electromagnetic fields to humans and, more specifically, the effects this exposure may have to human life health.
The control of the electromagnetic environment is a difficult task that depends on a number of parameters. Presently, such control is provided only on a theoretical basis. The World Health Organization (WHO) and the International Commission of Non-Ionising Radiation Protection (ICNIRP) have proposed maximum exposure limits of RF electromagnetic fields based on precautionary principles. These limits are maximum values of the electric and magnetic field strength to which humans may be exposed. Accordingly, it is desirable to measure the electromagnetic field constantly and in real-time in order to verify compliance of the regulations regarding radiation emissions from mobile communication antenna.
One problem faced by both the general public and public authorities is the difficulty of continuously measuring the RF emissions at any distance away from a given mobile communication antenna. As a result, since the electromagnetic environment cannot be continuously verified everywhere, the general public (and, in some instances) the authorities come in direct conflict with mobile network operators resulting in the delaying or even blocking of investments on such antenna systems that intend to be installed in residential and workplace areas, for example.
It is also known that the size of measurement devices placed on, or near, an antenna may adversely affect the performance of the antenna. Such a reduction in performance is undesirable.
It is an aim of the present invention to overcome, or at least mitigate at least some of the problems associated with the prior art.